Modular tool heads for use with circular surgical instruments

A port for insertion into a patient's colon and use during a surgical technique using a surgical stapler, the surgical stapler including a tool head and an anvil attachable to the tool head, said port comprising:

• a frame configured to engage the colon, the frame comprising:
• an annular inner ring portion defining an aperture that is sized and configured to permit the anvil in its entirety to be passed therethrough, said annular inner ring portion operably supporting a plurality of radially deployable barbs thereon;
• and
• an annular outer ring portion supported on said annular inner ring portion such that said annular inner ring portion may be selectively rotated relative to said annular outer ring portion between a first position wherein each of said radially deployable barbs does not protrude radially beyond an outermost perimeter of said annular outer ring portion to a second deployed position wherein a tissue engaging portion of each said barb protrudes radially beyond the outermost perimeter of said annular outer ring portion and wherein the port further comprises a sleeve that extends from said annular outer ring portion and is sized and configured to receive at least a portion of the tool head therein.